In recent years, the Material exchange Format (MXF) has been used as a data exchange format for exchanging material data between servers. An MXF file is mainly formed by items such as a header, a body, and a footer. The item “Header” stores various metadata information items. The item “Body” stores frame data including video data and audio data. The metadata information includes information necessary for playing back video and audio stored in the item “Body”.
The item “Header” is formed by repeated KLV structures, each of which is formed by the structure including a Key field, a Length field, and a Value field. The Key field indicates the data type of metadata information which is described as Value field. The Length field indicates the data length that the following Value field has. The Value field describes metadata information itself which is designated by the Key field.
When the Key field in the Header is broken, no KLV structure is detected, and thus metadata information might not be read out. In addition, when the Key field is broken, metadata information corresponding to the broken key field might be read as metadata information which corresponds to another key field.
Further, when the Length field in the Header is broken, metadata information which corresponds to a value field followed by the broken length field might not be accurately read out because the length of the Value field cannot be accurately known. In addition, when the Length field is broken, the KLV structure might not be detected because the head position of the next Key field is not detected.
As described above, when a Key field or a Length field is broken, metadata information following the broken part might not be accurately obtained.